SE Sa
the entire region.
Soil appears to be the dominating influence in forming the topographic
characteristics which have been listed. Only the more pronounced features are
outlined in the illustrations. The entire terrain is a repetition of those indicat-
ed features appearing in less pronounced appearance plus other features enum-
erated.
The steep flutings, vertical valleys or chutes found in the ravine walls of
the uplands have been considered as due to the effects of solution as observed
in basaltic and limestone regions under a tropical Climate.
Numerous hot springs, lack of detritus throughout the entire region and
the scarcity of surface flow in the uplands in contrast to the amount appearing
on the coastal plains indicate that surface flow is nota predominating factor in
forming topography.
The theory here presented is of the nature of a first hypothesis. With no
erosion process accounting for the listed features, the mentioned theory ap-
pears, at present, to be the logical conclusion.
NOTES
l/ Although the vegetation in the eastern Venezuela illustration is not typi-
cally savanna, the area is classified as semiarid by Peveril Meigs in
maps prepared for the Ankara Symposium on Arid Zone Hydrology (1953).
Vegetation indicates a more humid climate than that of the grassy sa-
vannas.
2/ Soil, the yearbook of Agriculture 1957 U.S. Dept. Agriculture
U.S. Government Printing Office Washington, D. C.
i
The Columbia Lippincott Gazetteer of the World
Columbia University Press New York, 1952
>
"Australian physiographers (apparently unique in this regard) have for
long recognized that the depth of ready erosion (upon rejuvination of ter-
rain) may be governed by the presence of unweathered hard rock beneath
the oxidized zone."